Chlorinated acyl peroxides and method for their manufacture



United States Patent CHLORINATED ACYL PEROXIDES AND METHOD FOR THEIRMANUFACTURE Albert L. Dittman, Jersey City, N. 1., and John M.Wrightson, Whittier, Califi, assignors to The M. W. Kellogg Company,Jersey City, N. J a corporation of Delaware 3 Claims. (Cl. 260-610) Thisinvention relates to the manufacture of perhalocarbons. In one of itsaspects, the invention relates to the manufacture of perhalocarbonplastics, oils, greases and waxes. More particularly in this aspect, theinvention relates to a method for the polymerization of perhalo-olefinsto produce normally liquid and solidperhalopolymers. Still moreparticularly in this latter aspect, the invention relates to a methodfor the polymerization of trifluorochloroethylene to produce normallyliquidand solid polymers of this monomer.

This invention is a division of our prior and copending applicationSerial No. 225,850, filed May 11, 1951 now U. 8. Patent 2,705,706,issued April 5, 1955; and a continuation-in-part of our prior andcopending application Serial No. 98,276, filed June 10, 1949, now U. S.Patent 2,636,908 issued April 2, 1953.

Normally liquid and solid perhalocarbons have been produced by thepolymerization of a monomer in the presence of certain promoters, and,in the case of liquids, also in the presence of a chain-transfersolvent. For example, under suitable conditions of temperature andresidence time, and in the presence-of trichloroacetyl peroxide,trifluorochloroethylene can be polymerized to obtain chemically andphysically stable, solid, polymers having a ariety of uses. Benzoylperoxide has been employed to produce liquid polymers. The disadvantagesof these promotors in comparison with the promoters of the presentinvention, reside in their being more expensive to produce, and'in beingunstable at relatively high temperatures. In the ease of benzoylperoxide, there :is the further disadvantage that the fragments ofpromoter attached to the polymer contain hydrogen which makes thepolymer less stable. I

It is, therefore, an object of the present invention to polymerizeper-halo-olefins under suitable conditions in the presence of a newpromoter to produce perhalopolymers.

Another object of the invention is to provide 'an improved method forproducing perhalomle'fiu polymers of predetermined chemical and physicalcharacteristics and high yields. I

Still another object of the invention "is to provide an improved methodfor producing polymers of trifiuo'rochloroethylene. I

A further object of the invention is to provide a novel promotersuitable for use in the polymerization of perhalo-olefins to produceperhalo-polymers.

A still further object of the invention is to provide a method forproducing a novel promoter suitable for use in the polymerization ofperhalo-olefins to produce perhalo-polymers.

Various other objects and advantages of the present invention willbecome apparent to those skilled in the art from the accompanyingdescription and disclosure.

As herein employed, perhalocarbons are defined as compounds consistingsubstantially exclusively of carbon and halogen with any degree ofunsaturation and con- ICC taining only negligible amounts of otherelements, such as hydrogen and oxygen, in a quantity less than about 2weight percent as impurities. These other elements are derived frommaterials utilized in the process as will hereinafter become apparent.'Perhalo-olefins are defined as perhalo-olefins having any degree of'unsa'turation, and consisting of halogens and carbon. Perfluoro-olefinsare defined as perhalo-olefins having any degree of unsaturation andconsisting of fluorine and carbon. Perfiu'orochloro-olefius are definedas perhalo-olefins consisting of fluorine, chlorine and carbon. Thepreferred 'perfiuorochloro-olefins of this invention are thosecontaining not more than one chlorine atom per carbon atom.

According to this invention, perhalo-olefins are homopolymerized orcopolymerized under suitable polymerization conditions in the presenceof a halogenated acyl peroxide having at least 6 carbon atoms permolecule as a promoter, to produce oils andjgreases at normalatmospheric temperature, and waxes, including hard waxes havingsoftening points extending to about 200 C., and normally solid materialof the nature of thermal plastics, in high yields with good selectivityfor the desired product.

The perhalo-olefins which may be "homopolymerized "or copolymer'ized inaccordance with the process of the invention include per'fluoro-olefinsand perfiuorochl'oroolefins, such as triflu'orochloroethylene,tetrafluoroethylene, perfluorobu'tadiene, difluorodichloroethyleneincluding both CFa CCl and CFCl'=CFCl, perfiuoropropene,perfluoromono'chloropropene, perfiuorobutene, periluoromonochlorobutene,diphenyldifluroethylene, etc. Typical examples of 'copolymerization of'the above perhalo-olefins include the copolyrtreriZat'ion oftrifluorochloroethylene and fiuorochloroisobutene; oftriiluorochloroethylene and diphenyldifiuoroethylene; oftrifluorochloroethylene and tetrafluoroethylene; er trifluoroc hl'oroethylene and vinylidene fluoride; of triiluorochloroethylene andvinyl fluoride; of trifluo'rochloroethylene and vinyl chloride; oftrifiuorochloroethy'lene and vinylidene chloride; oftri'fiuorochloroethylene and perfluor'opropene; oftrifluorochloroethylene and triiluoroethylene; and'of perfluorobutadieneand perfluorostyrene, etc.

The term polymerization includes, in its broadest sense, bothhomopolymerizat'ion and copolyrnerization of the perhalo-ole'fins withother compounds. The term homop'olymerization includes the use of up to5 percent of a comon'orner, which does not necessarily afiect thecharacteristics of the product, but which is used as a modifier.

In the polymerization "of trifluorochloroethylene, to which thisinventionhas particular application, to produce either normally liquidorsolid p'erhalo-polyme'r's, the promoter employed is a major factor ineffecting the pub ymeriza'tion and determining the molecular weight,yield and characteristics of the product produced. According to theinvention, as indicated above, polymerization or cop'olymeriz ation ofperhalof'olefins is carried out in the presence of a halogenated acy lperoxide having at least 6 carbon atoms per molecule, -as a promoter.Examples of such promoters include the completely halogenated propionylperoxides such as trifluorodichloropropionyl peroxide,trichlorodifluoropropinyl peroxide, tetrafluorochloropropionyl peroxide,tetrachlorofiuoropropionyl peroxide, and perchloropropionyl peroxide;and partially halogenated propionyl peroxides such as,tetrachloropropionyl peroxide, and the completely halogenated butyrylperoxides such as pentafluorodichlorobutyryl peroxide,pentachlorodifiuorobutyryl peroxide, tetrafiuorotrichlorobutyrylperoxide, tetrachlorotrifiuorobutyryl peroxide, and perchlorobutyrylperoxide; and partially halogenated butyryl peroxides such astetrachlorobutyryl peroxide, and the completely halogenated valerylperoxides such as septafluorodichlorovaleryl peroxide,pentafluorotetrachlorovaleryl peroxide, pentachlorotetrafluorovalerylperoxide,

and perchlorovaleryl peroxide; and the partially halogenated valerylperoxides such as tetrachlorovaleryl peroxide, etc. The completelyhalogenated peroxides are preferred.

The concentration of the halogenated acyl peroxide, used as a promoterin accordance with the process of the invention, is important indetermining the molecular weight, yield and characteristics of theproduct produced. In the case of producing normally solid polymers ofthe nature of thermoplastics, the amount of promoter used usually variesbetween about 0.01 and about 0.5 weight percent of the monomer in thereaction mixture, depending upon the molecular weight of the ultimateproduct to be produced. In the case of producing normally liquid andwaxy polymers, the amount of promoter used varies between about 0.5 andabout 10 weight percent of the monomer in the reaction mixture, with apreferred range between about 2 and about 6 weight percent of themonomer in the reaction mixture.

In general, it has been observed when producing polymers employing theaforementioned halogenated acyl peroxides having at least 6 carbon atomsper molecule, as promoters, an increase in the amount of promoter used,within the aforementioned range of concentrations, results in a decreaseof the molecular weight of the resulting product. In the case of thesolid plastic produced, the

N. S. T. value is proportional to the molecular weight and thereforeindicates, relatively, the molecular weight of the polymer produced. TheN. S. T. value is defined as the no-strength-temperature of the solidpolymer.

A preferred promoter, of the class of halogenated acyl peroxides havingat least 6 carbon atoms per molecule of the present invention, istrifluorodichloropropionyl peroxide. The preparation of this peroxide ischaracteristic of the method for the preparation of other peroxides ofthe group of halogenated acyl peroxides of this invention. This peroxidemay be prepared by first forming trifluorodichloropropionyl chloride(CF3CC12COC1). Trifluorodichloropropionyl chloride is prepared bybubbling chlorine and oxygen through trifluorotrichloropropene(CFaCCl=CCl2) in the presence of actinic radiation, (for example,ultra-violet light) to produce trifluorodichloropropionyl chloride, as aliquid.

Liquid trifluorodichloropropionyl chloride thus produced, is nextreacted with sodium peroxide (NazOz) suspended in aqueous sodiumchloride solution (20% by weight of sodium chloride) to yield thedesired trifluorodichloropropionyl peroxide. The quantity oftrifluorodichloropropionyl chloride reacted with sodium peroxide is inaccordance with stoichiometric requirements, although excesstrifluorodichloropropionyl chloride may also be used. The reaction iscarried out at a temperature in the range between about 20 C. and about0 C., and preferably at a temperature of about 16 C., in an open mixingvessel at atmospheric pressure. Reaction takes place almostinstantaneously.

The peroxide (trifluorodichloropropionyl peroxide) is recovered from thereaction mixture by extraction with Freon-11(trichloromonofluoromethane). The peroxide crystallizes when the Freonsolution is cooled to about 4 C. and is purified by washing andrecrystallizing in fresh Freon-l1. The purified peroxide is thendissolved in Freon-ll and diluted to the desired concentration forpolymerization.

The following examples will serve to illustrate the method for thepreparation of trifluorodichloropropionyl peroxide and may also beapplied to the preparation of other peroxides of the group ofhalogenated acyl peroxides of the present invention.

Example I 21.6 grams of trifluorodichloropropionyl chloride (which is3.4 grams in excess of the stoichiometric quan tity) was reacted with3.3 grams of sodium peroxide suspended in 248 grams of sodium chloridesolution (20% sodium chloride by weight) at 16 C. The above reactionproduced a yield of 10.3 grams of trifluorodichloropropionyl peroxide.

Example II 18.2 grams of trifluorodichloropropionyl chloride (which isthe stoichiometric quantity) was reacted with 3.3 grams of sodiumperoxide in 248 grams of sodium chloride solution (20% sodium chlorideby weight) at 16 C. The above reaction produced a yield of 10.7 grams oftrifluorodichloropropionyl peroxide.

Various modifications of the aforementioned process of the inventionwill be apparent to those skilled in the art, without departing from thescope of the invention.

We claim:

1. Trifluorodichloropropionyl peroxide, in which all fluorinesubstituents appear at the terminal carbon atoms.

2. A method for preparing trifluorodichloropropionyl peroxide whichcomprises: reacting trifluorodichloro propionyl chloride with sodiumperoxide suspended in an aqueous solution of sodium chloride at atemperature between about 20 C. and about 0 C. to producetrifluorodichloropropionyl peroxide, in which all fluorine substituentsappear at the terminal carbon atoms, as a product of the process.

3. A method for preparing trifluorodichloropropionyl peroxide whichcomprises: reacting trifluorodichloropropionyl chloride with sodiumperoxide suspended in an aqueous solution of sodium chloride at atemperature between about -20 C. and about 0 C. to produce a reactionmixture comprising trifluorodichloropropionyl peroxide, in which allfluorine substituents appear at the terminal carbon atoms; extractingtrifluorodichloropropionyl peroxide from said reaction mixture withtrichloromonofiuoromethane; and recovering crystals of trifiuorodichloropropionyl peroxide from the resulting mixture as a product of theprocess.

References Cited in the file of this patent

1. TRIFLUORODICHLOROPROPIONYL PEROXIDE, IN WHICH ALL FLUORINESUBSTITUENTS APPEAR AT THE TERMINAL CARBON ATOMS.